Shock absorber



Nov. 10, 1936.- w, c s-r 7 2,060,554

SHOCK ABSORBER Filed Jan. 9, 1935 INVENTOR W/zz/AM 4 095x57" ATTORNEYS Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE SHOCK ABSORBER William A. Chryst, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application January 9, 1935, Serial No. 946

3 Claims. (01. 188-89) This invention relates to improvements in 30 may be termed the working chamber. Within hydraulic shock absorbers. this working chamber the shaft 28 has a piston 40 It is among the objects of the present invenattached thereto so that said piston will rotate tion to provide a hydraulic shock absorber of comwith said shaft. As shown in Figure 2, this piston pact and simple design, capable of controlling 40 has a hub portion 4! and a wing providing op- 5 both the approaching and separating movements positely disposed vanes 42 and 43, the outer ends of the frame and axle of a vehicle. of which slidably engage the inner, annular wall Further objects and advantages of the present of the housing 23. This piston 40 is recessed as invention will be apparent from the following deat 45, this recess cooperating with the annular scription, reference being had to the accompanywall of the housing 23 to form a reservoir 46, 1O ing drawing wherein a preferred embodiment of which is of constant size and in which the fluid the present invention is clearly shown. is contained substantially at atmospheric pres- In the drawing: I sure. Figure l is a fragmentary side view of a vehicle The portion of the working chamber on the chassis, having a shock absorber equipped with side of the piston opposite the reservoir 46 is di- 15 the present invention attached thereto. vided into two fluid displacement chambers 50 Figure 2 is a cross sectional view of the shock and 5| by a stationary partition 52 secured within absorber taken substantially along the line 2-2 the shock absorber casing by the screw plugs 60 of Figure 3. of the fluid flow control devices, later described Figure 3 is a longitudinal sectional view taken and by a pin 53, one end of which extends into a 20 substantially along the line 33 of Figure 2. hole in the partition, the other into an opening Figure 4 is a fragmentary detailed sectional in the e d cover s shown in Figure 3, Th w t e along the line of Figure 3 a d hub 4| of the piston, as shown in Figure 2, slidably lustrating in detail one of the fluid flow control engages imilarly haped urface of t ty 5 devices. tion 52. In this partition fluid flow control de- 5 Referring to the drawing, the numeral 29 desigvices are provided which control the transfer of nates the frame of the Ve ic Wh c is Supported fluid between chambers 50 and 5| as the piston 40 upon the axle 2| by springs 22. is reciprocated. One fluid flow control device is The shock absorber comprises a cup-shaped cyprovided in the duct 55, this device regulating the 30 lindrical housing or casing 23 having perforated fluid flow from h mbers 50 d 5|, but per- 30 s 24 by means of Which the ousing is a c mitting no fluid to flow in a reverse direction beto the frame of the vehicle. As shown in Figure 3, tween said chambers. The other duct 56 has a t s ou 23 Comprises a cylindrical wall 25 valve acting in the opposite direction, thus perand an end Wall 26, the end wall having a central mitting fluid to flow only from chamber 5| to aperture 21 in which the one end of the Operating chamber 50. Inasmuch as both of these fluid flow 35 shaft 28 is journaled. A counterbored portion 29 control devicesare practically alike, only one will in the opening 21 is provided to receive a sealing be described detailedly. plug 30 so as to prevent fluid leaks at this point. Referring to Figure 4, we flnd that the duct 56 Housing 23 has a removable end cover 36 prohas an enlarged portion 51, providing a shoulder 40 vided with a central aperture coaxially aligning 58 which forms a seat for the flanged valve 59. 40 with the opening 21 in the end wall 26, in which The open end of this duct portion 51 extends tothe shaft 28 is also rotatably supported. The the outside of the shock absorber, it being inopen end of housing 23 is interiorly threaded to teriorly threaded to receive the plug 60. Plug 60' receive the clamping ring 3i which maintains has a washer 6i engaging its inner end, this the end cover 30 in proper position relatively to Washer acting as an abutment member for one 45 the integral end wall 26. Any suitable packing end of the spring 62 interposed between the ring 32 is provided in cooperating grooves formed washer and the flanged valve 59. This spring in the adjacent surfaces of the end cover 36 and yieldably maintains valve 59 in a position which clamping ring 3! so as to prevent fluid leaks at normally closes communication between chamthis point. Any suitable packing 33 held in posibers 5] .and 56 respectively. As the piston is ro- 50 tion relatively to the end cover 30 and the shaft tated clockwise as regards Figure 2, pressure is 28 by a gland 34 is provided to prevent fluid leaks exerted upon the fluid in displacement chamber along the shaft 28. 5| and, when said pressure attains a proper value, The space within the housing 23 between the valve 59 will be moved from its seat to permit a integral end wall 26 and the removable end cover restricted fluid flow from chamber 5| through 55 duct 56 into the chamber 50. The same is true as regards the flanged valve I60 provided in duct 55, which valve will permit fluid to flow from chamber 58 to the chamber 5| only when the fluid pressure within chamber 50 has attained a proper value in response to counter-clockwise rotation of the piston 40.

A groove 70 is provided in the peripheral surface of the end cover member 30 substantially midway between the inner surface of the end cover member, which slidably engages the piston 40, and the outer edge of the end cover member which is grooved to receive the packing 32. This annular groove leads into the opening in which the shaft 28 is journaled through a series of radial passages H provided in the end cover member. In the piston 40 a passage or duct 13 provides communication between the reservoir 46 and the opening in the hub of the piston through which shaft 28 extends.

The shaft, as may be seen in Figures 2 and 3, has a central passage 15 extending from its inner end adjacent the plug 30 toward the opposite end of the shaft. This shaft also has two annular grooves 16 and 1! provided in its peripheral surface, these grooves being in communication with the central longitudinal passage 15 through radial ducts or passages 18 and 19 respectively. As seen in Figure 3, the radial passages H in the end cover 30 align with the annular groove 16 in the shaft when the shock absorber is properly assembled, while duct or passage 12 of the piston aligns with the annular groove 11 in the shaft. The aforesaid ducts, passages and grooves provided in the end cover member, piston and shaft, form fluid-conducting devices to prevent fluid leaks to the outside of the shock absorber. If for any reason fluid should leak along the peripheral edge of the end cover member 30, that is, between said peripheral surface and the wall of the casing 23, due to the pressure on the working chambers, then said fluid, before reaching the packing 32, would enter the groove 10 in the end cover member, flow down through the radial passages 7|, enter the annular groove 16 in the shaft, and, flowing through duct 18 and passage 15, duct 19, groove 1'! in the shaft, would enter the reservoir through the passage 13 in the piston. Also, any pressure that might be exerted upon the fluid to cause it to flow along the contacting walls of the piston and integral end wall 26 of the housing, would enter the space between the plug 30 and the end of the shaft 28 and from there, flow to the reservoir in the casing via the passage 28 in the shaft, duct 19 and radial groove 11 and through the duct 13 in the piston. From this it may be seen that fluid leaks from the shock absorber, due to the high pressures generated therein, are practically eliminated.

Due to fluid leaks past the piston, the fluid supply in chambers 50 and 5| might possibly be reduced and thus affect the efiicient operation of the shock absorber, these fluid leaks not being to the outside of the shock absorber, but from the chambers into the reservoir. To replenish the supply if such a leak has occurred, applicant pro vides two fluid supply valves 80 and 8| in the piston, each being adapted to permit fluid to flow from the reservoir to a respective displacement chamber, but not from the chamber into the reservoir.

If the axle 2| of the vehicle is moved to approach the frame 20, a clockwise movement of the shock absorber obtains and therefore pressure is exerted upon the fluid in chamber 51,

causing a flow from said chamber past the valve 59 in duct 56 into chamber 50, the restriction to the fluid flow past said valve 59 resisting this approaching movement. At the same time if the fluid supply in chamber 50 has been diminished by fluid leaks mentioned above, then valve 80 may open against the eifect of its spring to permit a supply of fluid to flow from the reservoir 46 into said chamber 50.

As the axle is moved away from the frame in response to the rebounding movement of spring 22 or the upward movement of the vehicle frame 20, a counter-clockwise rotation of the shock absorber is obtained, causing the piston to exert pressure upon the fluid within chamber 50, thus a restricted flow of fluid is permitted by valve 50 through duct 55 into the chamber 5|, the restriction of valve 60 to the fluid flow causing the shock absorber to resist this separating movement between the vehicle axle and frame.

In Figure 1 the connection of the shock absorber with the axle is shown. The end of the shaft 28 extending from the shock absorber has one end of an arm 90 attached thereto, the opposite end of said arm having one end of a link 9| swivelly secured thereto, the other end of said link being secured to a bracket 93 which is anchored to the axle 2| in any suitable manner.

Among the features of the present invention are compactness and simplicity of the device, the recess in the piston forming the reservoir 46 being the contributing factor to the compact structure, for it may readily be seen that providing the shock absorber with an outside reservoir would necessitate a larger structure. In this instance the piston is so designed that, even though it is recessed to provide a reservoir, still ample fluid displacement space is provided in the shock absorber to permit it to offer sufficient resistance for body and axle control.

Another feature is the accessibility of the valves from outside the shock absorber, thus permitting adjustments, repairs or replacements to be made in the actual control elements of the shock absorber without necessitating the arduous task of removing the entire device from the vehicle.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claim which follow.

What is claimed is as follows:

1. A hydraulic shock absorber comprising, in combination, a cup-shaped casing; a rotatable piston in said casing, having a recess cooperating with the casing wall to provide a fluid reservoir; a partition cooperating with the piston to form two fluid displacement chambers, said partition having passages, each of which is provided with a mechanism including valve, spring and plug members to control fluid flow between said chambers in response to rotation of the piston, the plug member of said fluid flow control mechanisms acting also to secure the partition within the casing; and check valves in the piston each adapted to permit fluid to flow from the reservoir into a displacement chamber, but to prevent a reverse flow.

2. A hydraulic shock absorber comprising, in combination, a cup-shaped casing; a rotatable piston in said casing, having a recess cooperating with the casing wall to provide a fluid reservoir; a partition cooperating with the piston to form two fluid displacement chambers, said partition having two separate passages providing communication between said chambers; a fiuid flow con trol device in each passage, comprising a screw plug and a spring loaded pressure relief valve, each valve being accessible from outside the casing by removal of its screw plug, the plugs of said passages providing means for holding the partition in position; and check valves in the piston, permitting fluid to flow only from the reservoir into the respective displacement chambers.

3. A hydraulic shock absorber comprising, in combination, a cup-shaped housing provided with a removable end plate; a shaft rotatably supported by a wall of the housing and said end plate so as to be substantially coaxial of the housing, said shaft having a plurality of annular grooves in its peripheral surface and a longitudinal duct connecting said grooves; an annular duct in the peripheral surface of the end plate, connected with one of the grooves of the shaft by radial passages in the end plate; a piston in the housing secured to the shaft to rotate therewith and having a recess which cooperates with the housing to provide a fluid reservoir; a duct in the piston connecting said reservoir with another groove in the shaft; and leak-resisting packings provided between the shaft and end plate and the housing and end plate.

WILLIAM A. CHRYST. 

